Hello Everyone,
If you are reading this you must have listened from a lot of people about the importance of ‘The OSI model’ in networking. Let me present you with a quick read on the mentioned topic……………………(Here, we start)
It’s all about -
PHYSICAL LAYER — — — — — — —(Layer 1)
DATA LINK LAYER — — — — — — — (Layer 2)
NETWORK LAYER — — — — — — — -(Layer 3)
TRANSPORT LAYER — — — — — — — (Layer 4 )
SESSION LAYER — — — — — — — — (Layer 5)
PRESENTATION LAYER — — — — — (Layer 6)
APPLICATION LAYER — — — — —(Layer 7)
(A) PHYSICAL LAYER — — — — — — — - (Layer 1)-
Here, The data is transmitted over the network in the form of bits.
Examples- Ethernet Cables, Fibre Optic Cables, Hubs, Wireless Access Points, Bluetooth, etc.
(B) DATA LINK LAYER — — — — — — — (Layer 2)-
Here, encapsulation of data into frames takes place. Then, the transmission of these frames takes place over the network.
Detection of error and it’s correction also takes place here.
Another function includes Identification of network devices using their MAC address.
This layer is also responsible for flow control.
Examples- Switches, Bridges, etc.
(C) NETWORK LAYER — — — — — — — -(Layer 3)-
Whenever we talk about this layer, we talk about routing, addressing(IPv4, IPv6), Switching, etc.
Here, data flows in the form of packets.
Examples- Routers for traffic forwarding, IPv4 Protocol and IPv6 Protocol for IP addressing, Internet Control Message Protocol (ICMP) for troubleshooting, etc.
(D) TRANSPORT LAYER — — — — — —- (Layer 4 )-
Here, the concept of TCP(Transmission Control Protocol) and UDP(User Datagram Protocol) comes into play.
If you are wondering what are the above-mentioned protocols. You can find out about them on the internet pretty easily.
The only thing I should mention here is TCP is more reliable (due to 3-way handshake method) than UDP.
Whenever data travels in this layer, it's in the form of SEGMENTS (if using TCP) or DATAGRAMS (if using UDP).
Examples- TCP, UDP, Firewalls, etc.
(E) SESSION LAYER — — — — — — — — (Layer 5)
The main purpose includes setting up sessions, maintaining these sessions and closing a session
Here, the session is basically a connection or a conversation that is kept separate from other sessions.
Examples- NetBIOS (Used by computers to share files over a network)
(F) PRESENTATION LAYER — — — — — -(Layer 6)
In this layer data formatting(for proper compatibility between devices) and data encryption takes place.
Example- Open any mail you had received. In that mail press on view details. there will be a field mentioned as security in there, which is designated as TLS(Transport Layer Security). If it’s not TLS then please be careful.
Other Examples- SSL, GIF, JPG, TIF, SVG, PNG, HTML, XML, PHP, JavaScript
(G) APPLICATION LAYER — — — — — — (Layer 7)
This layer provides application services.
With the help of these services, user communicate with the computer.
Example- Domain Name Service (DNS), Remote Access (TELNET, SSH), Web Browsing (HTTP, HTTPS), E-mail (POP3, IMAP, SMTP) etc.
Well, you can put it like this (To Remember)-
Perfection_Do_Not_Tell_Someones_Positive_Attitude
or
You can make your own short key phrases
Make your own key phrase using these 7 layers and
Comment down below